PowerShell is an automation platform and scripting language for
Windows and Windows Server that allows you to simplify the
management of your systems. Unlike other text-based shells,
PowerShell harnesses the power of the .NET Framework, providing
rich objects and a massive set of built-in functionality for taking
control of your Windows environments.

Windows PowerShell is a task automation and configuration
management framework from Microsoft, consisting of a command-line
shell and associated scripting language built on the .NET
Framework. PowerShell provides full access to COM and WMI, enabling
administrators to perform administrative tasks on both local and
remote Windows systems as well as WS-Management and CIM enabling
management of remote Linux systems and network devices.

Here is a picture of how Windows PowerShell window looks like:

For more information on Windows PowerShell, see
https://msdn.microsoft.com/en-us/powershell/.

For technical references on Windows PowerShell 5.0, see
https://technet.microsoft.com/en-us/library/hh847741.aspx.